U.S. patent number 10,427,955 [Application Number 15/327,194] was granted by the patent office on 2019-10-01 for irradiation chamber for liquid purification apparatus, purification apparatus and beverage dispenser.
This patent grant is currently assigned to Societe des Produits Nestle S.A.. The grantee listed for this patent is NESTEC S.A.. Invention is credited to Celine Rimbault, Renaud Sublet.
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United States Patent |
10,427,955 |
Rimbault , et al. |
October 1, 2019 |
Irradiation chamber for liquid purification apparatus, purification
apparatus and beverage dispenser
Abstract
The invention relates to an irradiation chamber (300) for a
liquid purification apparatus using ultraviolet light irradiation
against the reproduction of pathogenic microorganisms, comprising
an inlet portion (302), an outlet portion (303), and a main portion
(301) having an elongated shape, the irradiation chamber (300)
having an internal surface defining an cavity, the irradiation
chamber (300) being provided with ultraviolet light emitting means
configured to irradiate liquid in the irradiation chamber (300)
with ultraviolet light, the main portion (301) having a shape
enlarged compared to the inlet portion (302). The internal surface
of the irradiation chamber (300) defining the cavity is a three
dimensional rounded surface, having no edge which forms a recess.
The invention also relates to a liquid purification apparatus and
to a beverage dispenser.
Inventors: |
Rimbault; Celine (Vittel,
FR), Sublet; Renaud (Vittel, FR) |
Applicant: |
Name |
City |
State |
Country |
Type |
NESTEC S.A. |
Vevey |
N/A |
CH |
|
|
Assignee: |
Societe des Produits Nestle
S.A. (Vevey, CH)
|
Family
ID: |
51211640 |
Appl.
No.: |
15/327,194 |
Filed: |
July 9, 2015 |
PCT
Filed: |
July 09, 2015 |
PCT No.: |
PCT/EP2015/065725 |
371(c)(1),(2),(4) Date: |
January 18, 2017 |
PCT
Pub. No.: |
WO2016/008803 |
PCT
Pub. Date: |
January 21, 2016 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20170158529 A1 |
Jun 8, 2017 |
|
Foreign Application Priority Data
|
|
|
|
|
Jul 18, 2014 [EP] |
|
|
14177691 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C02F
1/325 (20130101); A61L 2/10 (20130101); A61L
9/20 (20130101); C02F 2303/04 (20130101); C02F
2307/10 (20130101); C02F 2201/3222 (20130101); C02F
2201/3227 (20130101); C02F 2201/326 (20130101); C02F
1/008 (20130101); C02F 2201/3224 (20130101) |
Current International
Class: |
C02F
1/32 (20060101); A61L 9/20 (20060101); A61L
2/10 (20060101); C02F 1/00 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
2393593 |
|
Jan 2004 |
|
CA |
|
2009108045 |
|
Sep 2009 |
|
WO |
|
Primary Examiner: Tai; Xiuyu
Attorney, Agent or Firm: K&L Gates LLP
Claims
The invention claimed is:
1. An irradiation chamber for a liquid purification apparatus using
ultraviolet light irradiation against reproduction of pathogenic
microorganisms, the irradiation chamber comprising an inlet
portion, an outlet portion, and a main portion having an elongated
shape comprising a cylindrical part having a volume of 200 mL or
less, the main portion connected to the inlet portion and the
outlet portion by smoothly curved connecting portions each composed
of curved surfaces having a curvature radius greater than or equal
to a radius of the cylindrical part and greater than or equal to
0.5 cm, the irradiation chamber having an internal surface defining
a cavity, the irradiation chamber comprising an ultraviolet light
emitting member configured to irradiate a liquid in the irradiation
chamber with ultraviolet light, the main portion having a shape
enlarged compared to the inlet portion, and the internal surface of
the irradiation chamber defining the cavity is a three dimensional
rounded surface having no edge which forms a recess.
2. The irradiation chamber according to claim 1, wherein the
internal surface of the irradiation chamber defining the cavity is
a surface of revolution whose generatrix is a portion of a curve
having no cusp all along the portion of the curve.
3. The irradiation chamber according to claim 1, wherein the main
portion of the irradiation chamber has a length between 5 cm and 15
cm inclusive.
4. The irradiation chamber according to claim 1, wherein the main
portion of the irradiation chamber has an internal constant cross
section having a surface area between 0.5 cm.sup.2 and 4 cm.sup.2
inclusive.
5. The irradiation chamber according to claim 1, wherein the outlet
portion is collinear to the inlet portion.
6. The irradiation chamber according to claim 1, wherein the outlet
portion is substantially orthogonal with the inlet portion.
7. The irradiation chamber according to claim 1, wherein the
ultraviolet light emitting member comprises ultraviolet light
emitting diodes.
8. The irradiation chamber according to claim 1, wherein the
ultraviolet light emitting member comprises optical fiber portions
which are connected to at least one ultraviolet light source and
which are configured to transmit ultraviolet light from said at
least one source into the irradiation chamber.
9. A liquid purification apparatus comprising an irradiation
chamber using ultraviolet light irradiation against the
reproduction of pathogenic microorganisms, the irradiation chamber
comprising an inlet portion, an outlet portion, and a main portion
having an elongated shape comprising a cylindrical part having a
volume of 200 mL or less, the main portion connected to the inlet
portion and the outlet portion by smoothly curved connecting
portions each composed of curved surfaces having a curvature radius
greater than or equal to a radius of the cylindrical part and
greater than or equal to 0.5 cm, the irradiation chamber having an
internal surface defining a cavity, the irradiation chamber
comprising an ultraviolet light emitting member configured to
irradiate a liquid in the irradiation chamber with ultraviolet
light, the main portion having a shape enlarged compared to the
inlet portion, and the internal surface of the irradiation chamber
defining the cavity is a three dimensional rounded surface having
no edge which forms a recess.
10. The liquid purification apparatus according to claim 9, wherein
the internal surface of the irradiation chamber defining the cavity
is a surface of revolution whose generatrix is a portion of a curve
having no cusp all along the portion of the curve.
11. The liquid purification apparatus according to claim 9, wherein
the main portion of the irradiation chamber has a length between 5
cm and 15 cm inclusive.
12. The liquid purification apparatus according to claim 9, wherein
the main portion of the irradiation chamber has an internal
constant cross section having a surface area between 0.5 cm.sup.2
and 4 cm.sup.2 inclusive.
13. The liquid purification apparatus according to claim 9, wherein
the outlet portion is collinear to the inlet portion.
14. The liquid purification apparatus according to claim 9, wherein
the ultraviolet light emitting member comprises ultraviolet light
emitting diodes.
15. A beverage dispenser comprising a liquid purification apparatus
comprising an irradiation chamber using ultraviolet light
irradiation against the reproduction of pathogenic microorganisms,
the irradiation chamber comprising an inlet portion, an outlet
portion, and a main portion having an elongated shape comprising a
cylindrical part having a volume of 200 mL or less, the main
portion connected to the inlet portion and the outlet portion by
smoothly curved connecting portions each composed of curved
surfaces having a curvature radius greater than or equal to a
radius of the cylindrical part and greater than or equal to 0.5 cm,
the irradiation chamber having an internal surface defining a
cavity, the irradiation chamber comprising an ultraviolet light
emitting member configured to irradiate a liquid in the irradiation
chamber with ultraviolet light, the main portion having a shape
enlarged compared to the inlet portion, and the internal surface of
the irradiation chamber defining the cavity is a three dimensional
rounded surface, having no edge which forms a recess, the main
portion configured to purify a beverage by ultraviolet irradiation
before delivery of the beverage.
16. The beverage dispenser according to claim 15, wherein the
internal surface of the irradiation chamber defining the cavity is
a surface of revolution whose generatrix is a portion of a curve
having no cusp all along the portion of the curve.
17. The beverage dispenser according to claim 15, wherein the main
portion of the irradiation chamber has a length between 5 cm and 15
cm inclusive.
18. The beverage dispenser according to claim 15, wherein the main
portion of the irradiation chamber has an internal constant cross
section having a surface area between 0.5 cm.sup.2 and 4 cm.sup.2
inclusive.
19. The beverage dispenser according to claim 15, wherein the
outlet portion is collinear to the inlet portion.
20. The beverage dispenser according to claim 15, wherein the
ultraviolet light emitting member comprises ultraviolet light
emitting diodes.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
The present application is a National Stage of International
Application No. PCT/EP2015/065725, filed on Jul. 9, 2015, which
claims priority to European Patent Application No. 14177691.4,
filed Jul. 18, 2014, the entire contents of which are being
incorporated herein by reference.
FIELD OF THE INVENTION
The invention relates to an irradiation chamber for a liquid
purification apparatus, using ultraviolet irradiation against the
reproduction of pathogenic microorganisms. In particular, the
invention relates to an irradiation chamber for a small liquid
purification apparatus and to a beverage dispenser comprising such
a liquid purification apparatus, for example a water fountain.
BACKGROUND OF THE INVENTION
The present invention relates generally to liquid purification
apparatuses comprising an irradiation chamber for liquid
purification. The present invention also relates to a beverage
dispenser comprising such a purification apparatus.
One of the most essential tasks in purifying liquids such as water
for drinking is disinfection, so as to ensure that any pathogenic
microorganisms (e.g. bacteria, viruses, and protozoans) present in
the water cannot cause illness in anyone who drinks it. It is known
to perform this disinfection by the process of ultraviolet (UV)
irradiation, where a volume of water being treated is bombarded
with high-energy radiation in the form of UV light. The UV light
damages the DNA and RNA of the pathogenic microorganisms,
destroying their ability to reproduce and effectively neutralizing
their ability to cause disease.
Since such systems use light to disinfect, their effectiveness is
reduced on liquid which is not naturally clear or which has not
been filtered to remove suspended solids. The scope of
"purification," for the purposes of this document, should thus be
understood as encompassing the disinfection of liquid in which
turbidity is minimal.
Traditional UV liquid purification systems have employed
gas-discharge lamps as UV sources, in particular mercury-vapor
lamps. Recently, it has become more and more common to employ
ultraviolet light-emitting diodes (UV-LEDs) as a source of
ultraviolet light for irradiation. UV-LEDs have numerous
advantageous aspects which makes them appealing for use in an
ultraviolet liquid purification system, notably their compact size,
robustness, and lack of toxic components such as the mercury vapor
found in conventional lamps. The solid-state nature of UV-LEDs also
enables them to be switched on and off instantly, a further
advantage relative to conventional gas-discharge lamps.
There are several examples in the prior art of UV-LEDs being
employed to purify a liquid by ultraviolet irradiation. For
example, the document CN 202175579 describes an irradiation device
in which a single tube is spiraled around an array of UV-LEDs, and
the document KR 20110007554 describes a faucet with a built-in
UV-LED sterilizer for treating the liquid issuing from it. In
addition, the document KR 20040073732 describes a system for
purifying water that is drawn from a reservoir and conducted
through a sterilizer directly to a nozzle for dispensing.
In a general manner, to ensure an efficient purification of the
treated liquid, said liquid has to be irradiated by ultraviolet for
a sufficient time. The known purification apparatuses commonly
comprise an irradiation chamber where the liquid is irradiated.
Thanks to the volume provided in this irradiation chamber, the
corresponding volume of liquid may be irradiated and purified,
making this volume of purified liquid immediately available. The
volume of the irradiation chamber also reduces the average velocity
of the liquid flowing in the irradiation chamber, thus enhancing
the residence time of the liquid in said chamber, and so the
irradiation time.
Typical irradiation chambers have substantially the shape of a
cylinder, closed at each end by a straight wall.
The applicant has found that, in classical irradiation chamber,
many dead volumes exist. "Dead volumes" are parts of the chamber
where the fluid stagnates, even when a fluid stream is established
in the irradiation chamber. Such dead volumes should be avoided
because they reduce the effective volume of the chamber: when part
of the liquid stagnates, the remaining part of the liquid in the
irradiation chamber flows quicker than it would without dead
volumes. Dead volumes also promote the formation of inorganic
deposits in the irradiation chamber.
The applicant has also found that dead volumes generally exist
around the inlet in the irradiation chamber. Thus, the liquid
entering the irradiation chamber is not efficiently treated as soon
as it enters the chamber, i.e. from said inlet in the irradiation
chamber.
In small purification apparatuses such as those employed in water
fountains, the irradiation chamber has a relatively small volume
(e.g. 100 mL to 200 mL). Dead volumes are a problem particularly
acute in such small irradiation chambers, because any loss in the
volume actually available and used for treating the liquid should
be avoided, or else, in order to obtain a certain minimum
irradiation time of all the liquid flowing out of the irradiation
chamber, the volume of the chamber must be increased and/or the
flow rate decreased. It is not possible to wait for the fluid
present in the chamber to be naturally mixed and homogenized,
because generally the quantity of liquid to be delivered compared
to the volume of the irradiation chamber imposes a significant
continuous flow in the irradiation chamber.
Adding a mixer, which creates a turbulent flow, may be
contemplated. However, using a mixer is not efficient in all
reactor shapes and may have other drawbacks. For example, a power
supply may be required, or this may increase the maintenance needs.
Using a line having no enlarged irradiation chamber (i.e. the
irradiation is performed in a portion of the hose forming the line)
may be contemplated, but this is not possible in most applications
because of the irradiation time required for disinfection. Placing
baffles inside the irradiation chamber may also be contemplated.
But the baffles create corners in the irradiation chamber which may
favour the development of microorganisms and biofilm formation.
It is therefore an objective of the present invention to provide an
irradiation chamber for a liquid purification apparatus using
ultraviolet irradiation that solves or reduces at least one of the
above mentioned drawbacks.
SUMMARY OF THE INVENTION
In a first aspect of the invention there is provided an irradiation
chamber for a liquid purification apparatus using ultraviolet light
irradiation against the reproduction of pathogenic microorganisms,
comprising an inlet portion, an outlet portion, and a main portion
having an elongated shape, the irradiation chamber having an
internal surface defining a cavity, the irradiation chamber being
provided with ultraviolet light emitting means configured to
irradiate liquid in the irradiation chamber with ultraviolet light,
the main portion having an enlarged shape compared to the inlet
portion. The internal surface of the irradiation chamber defining
the cavity is a three dimensional rounded surface, having no edge
which forms a recess.
The smoothly rounded surface defining the irradiation chamber
reduces the dead volumes in said chamber. All or almost all the
volume of the chamber is used for the purification of the liquid
which flows in said chamber.
In an embodiment of the invention, the internal surface of the
irradiation chamber defining the cavity is a surface of revolution
whose generatrix is a portion of a curve having no cusp all along
said portion of the curve. In other word, the mathematical function
which defines generatrix of this surface of revolution is
differentiable all along the part of the curve defining the
surface.
The main portion of the irradiation chamber may be connected to the
inlet and outlet portions by smoothly curved connecting portions.
The main portion may in particular comprise a cylindrical part. In
this case, the connecting portions may be composed of curved
surfaces each having a curvature radius greater than or equal to
the radius of the cylindrical part. In particular, the connecting
portions are composed of curved surfaces each having a curvature
radius greater than or equal to 0.5 cm.
In an embodiment, the main portion of the irradiation chamber may
have a length between 5 and 15 cm inclusive. The main portion of
the irradiation chamber may have an internal constant cross section
having a surface between 0.5 cm.sup.2 and 4 cm.sup.2 inclusive.
Typically, the volume of the main portion of the irradiation
chamber may be 200 mL or less, and preferably around 100 mL.
In a configuration of the invention, the outlet portion is
collinear to the inlet portion. In another configuration, the
outlet portion is substantially orthogonal with the inlet
portion.
The ultraviolet light emitting means may comprise ultraviolet light
emitting diodes. Alternatively, the ultraviolet light emitting
means may comprise optical fiber portions which are connected to at
least one ultraviolet light source and which are configured to
transmit ultraviolet light from said at least one source into the
irradiation chamber.
The invention also relates to a purification apparatus comprising
an irradiation chamber as previously described. The invention
finally relates to a beverage dispenser such as a water fountain
comprising such a liquid purification apparatus, configured to
purify the beverage before delivery by ultraviolet irradiation.
BRIEF DESCRIPTION OF THE DRAWINGS
Additional features and advantages of the present invention are
described in, and will be apparent from, the description of the
presently preferred embodiments which are set out below with
reference to the drawings in which:
FIG. 1 is a schematic depiction of an example of liquid
purification apparatus comprising an irradiation chamber;
FIG. 2A is a schematic representation of an irradiation chamber for
a small purification apparatus, said irradiation chamber having the
design generally implemented in the state of the art;
FIG. 2B is a schematic representation of a section of the
irradiation chamber of FIG. 1, in which the streamlines of a liquid
flowing in the irradiation chamber are schematically
represented;
FIG. 3A is a schematic representation of an irradiation chamber
according to an embodiment of the invention;
FIG. 3B is a schematic representation of a section of the
irradiation chamber of FIG. 4, in which the streamlines of a liquid
flowing in the irradiation chamber are schematically
represented;
FIG. 4 is a schematic representation of a section of the
irradiation chamber according to another embodiment of the
invention.
DETAILED DESCRIPTION OF THE INVENTION
For a complete understanding of the present invention and the
advantages thereof, reference is made to the following detailed
description of the invention.
The invention is further described with reference to the following
examples. It will be appreciated that the invention as claimed is
not intended to be limited in any way by these examples.
It should also be appreciated that various embodiments of the
present invention can be combined with other embodiments of the
invention and are merely illustrative of the specific ways to make
and use the invention and do not limit the scope of the invention
when taken into consideration with the claims and the following
detailed description.
FIG. 1 is a schematic depiction of a liquid purification apparatus
100, in particular a purification apparatus comprised in a beverage
dispenser such as a water fountain. The following description of a
liquid purification apparatus relates to the general architecture
of an example of liquid purification apparatus using ultraviolet
irradiation. This general description may relate to both an
apparatus as known in the state of the art and an apparatus
according to an embodiment of the invention, as the present
invention relates in particular to the irradiation chamber used in
such a purification apparatus and does not change the general
architecture of such an apparatus.
The liquid purification apparatus 100 is provided a reservoir 101
which contains a volume of liquid 102. In this embodiment the
liquid 102 is water, but may optionally be any liquid of sufficient
transparency. The liquid 102 is drawn from the reservoir 101
through the pump tube 103 and into the pump 104. From the pump 104,
the liquid 102 is conducted into the circulation tube 105.
The circulation tube 105 extends from the pump 104 through the
primary irradiation device 106, as shown, establishing fluid
communication between the pump 104 and the discharge port 107 of
the purification apparatus.
In the primary irradiation device 106, the liquid is purified by UV
irradiation. In the represented embodiment, the irradiation device
106 comprises a tubular structure, with an internal surface 108.
The internal surface 108 is reflective, being fabricated preferably
from a highly-polished metal or alternately covered with a
reflective metal foil. A plurality of primary ultraviolet
light-emitting diodes (UV-LEDs) 109 is provided upon the interior
surface 108 of said primary irradiation device 106 so that they
project the ultraviolet radiation 110 inside an irradiation chamber
111.
The irradiation chamber is described in detail with reference to
FIGS. 2 to 4.
After having been irradiated and thus disinfected in the
irradiation chamber 111, the liquid 102 flows to the discharge port
107 and is discharged from the apparatus 100.
Optionally, the purification apparatus may be further provided with
a secondary irradiation device 112 comprising at least one
secondary UV-LED 113. The secondary irradiation device 112 projects
ultraviolet rays 110 on the discharge port 107, for sterilizing the
discharged fluid.
The output and number of UV-LEDs 109, 113 disposed in the primary
and secondary irradiation devices 106 and 112 may vary according to
the particular characteristics of the apparatus 100 and the
application in which it is to be employed.
In the represented embodiment, the apparatus 100 further comprises
a control means 114, which is configured to electrically control
the operation of the primary and secondary irradiation means 106
and 112 and the pump 104. Preferably, the control means 114 also
communicates with a photosensor 115 disposed within the primary
irradiation device 106. The control means 114 uses the output of
the photosensor 115 to calibrate the intensity of the ultraviolet
radiation 110 emitted from the primary UV-LEDs 109, as well as to
monitor the operation of the apparatus 100 and warn the user of any
malfunctions.
While the apparatus discussed herein employs a photosensor 115, it
should be understood that an apparatus 100 may be configured with
other sensors (e.g. flow meters, water clarity sensors,
thermocouples, etc.) which communicate with the control means 114
and which permit it to continually adjust the parameters of the
operation of the liquid purification means. The exact configuration
and program of operation of the control means 114 will thus vary
according to the application in which the liquid purification
device is to be employed.
FIGS. 2A, 2B, 3A and 3B are schematic representations of
irradiation chambers for small purification apparatuses, and more
particularly representation of the cavity defined by the internal
surface of the irradiation chambers. The represented purification
chambers may correspond to the purification chamber 111 of a
purification apparatus as represented in FIG. 1. Of course, such
purification chambers may be used in various types of apparatuses
and applications, not limited to beverage dispensers.
The purification chamber 200 represented in FIG. 2A has a typical
design according to the state of the art. The purification chamber
200 comprises a main portion 201, an inlet portion 202 and an
outlet portion 203.
The main portion 201 (and more specifically its internal surface)
has the shape of a cylinder with closed end. The ends of the
cylinder forming the main portion 201 are closed by straight walls
204. The inlet portion 202 and the outlet portion 203 are connected
to the walls 204.
At each end of the main portion 201, the walls form a recess or
corner 205 inside the main portion, at the periphery of said main
portion end.
In the corner 205, inorganic deposit may occur. In addition, dead
volumes 206 are created in the corners 205. Dead volumes correspond
to parts of the chamber where the fluid stagnates, or flows very
slowly compared to the average fluid velocity in the irradiation
chamber.
FIG. 2B illustrates this phenomenon. FIG. 2B is a representation of
a section of the irradiation chamber of FIG. 1. The streamlines of
a liquid flowing in the irradiation chamber 200 from the inlet
portion 202 to the outlet portion 203 are schematically represented
by arrows. The represented flow is only illustrative, but shows
that the dead volumes 206 (hatched in FIG. 3) exist in particular
around the inlet and the outlet of the main portion 201, in the
corner formed between the walls 204 and the cylindrical wall 207 of
the main portion 201. As a liquid flowing from the inlet portion
202 to the outlet portion 203 does not circulate in the dead
volumes, the efficient volume of the chamber used to slow the
liquid and ensure a sufficient residence time in the irradiation
chamber (in particular in the main portion 201) is reduced compared
to the geometrical (whole) volume of the chamber. Dead volumes also
promote formation of inorganic deposit in the irradiation
chamber.
In particular, dead volumes 206 generally exist around the inlet in
the main portion 201 of the irradiation chamber. Thus, a liquid
entering in the main part 201 is not efficiently treated as soon as
it enters.
FIG. 3A is a schematic representation of an irradiation chamber 300
according to an embodiment of the invention. It is especially
designed for a small purification apparatus such as a potable water
fountain.
The irradiation chamber 300 has a main portion 301 which is
substantially cylindrical, an inlet portion 302 and an outlet
portion 303. Compared to the irradiation chamber of FIG. 1, the
inlet potion 302 and the outlet portion 303 of the irradiation
chamber represented in FIG. 3 are connected to the main portion 301
by smoothly curved, rounded, connecting portions 304, 305.
In particular, the connecting portions 304, 305 have a progressive
change in their respective concavity. This results in an
irradiation chamber defining a cavity having an internal surface
having no sharp edge which forms a recess or a corner. The internal
surface of the irradiation chamber defines its internal volume, in
which the liquid to be disinfected flows. In a general manner, the
irradiation chamber according to any embodiment of the invention
defines a cavity having a rounded internal surface having smooth
changes of concavity.
In a particular embodiment of the invention, the surface of the
cavity defined by the irradiation chamber is a surface of
revolution. There is no cusp along the generatrix of this surface
of revolution. In other word, the mathematical function which
defines generatrix of this surface of revolution is differentiable
all along the part of the curve defining the surface.
Because there is no recess in the internal surface of the
irradiation chamber, inorganic deposits are prevented. A liquid
crossing the irradiation chamber flows in the whole volume of the
irradiation chamber. There is no significant dead volume, or, at
least, the dead volumes are strongly limited.
FIG. 4 shows a schematic representation of a section of the
irradiation chamber according to another embodiment of the
invention. In this embodiment, the irradiation chamber 400 has a
main portion 401 which is substantially cylindrical, an inlet
portion 402 and an outlet portion 403. The outlet portion is
substantially orthogonal to the inlet portion. The irradiation
chamber and the cavity that it defines is thus L-shaped. Of course,
any angle value may be formed between the inlet portion 402 and the
outlet portion 403 without departing from the invention.
As in the embodiment of the invention shown in FIG. 3, the inlet
potion 402 is connected to the main portion 401 by smooth, rounded,
first connecting portion 404. The second connecting portion 405
connecting the main portion 401 to the outlet portion 403 is an
elbow. The so formed elbow is preferably as large and rounded as
possible.
As shown in the above-described embodiment of the invention, an
irradiation chamber according to the invention has an internal
surface having no edge forming a corner.
Many configurations are possible. The irradiation chamber has an
elongated shape, for an easier positioning of the ultraviolet light
emitting means and an enhanced irradiation time of the liquid
flowing in the irradiation chamber. The light ultraviolet light
emitting means are, in a general manner, means able to irradiate
ultraviolet light in the irradiation chamber. The light ultraviolet
light emitting means may comprise for example ultraviolet light
emitting diodes (UV-LEDs) or optical fiber portions connected to at
least one ultraviolet light source which are configured to transmit
ultraviolet light in the irradiation chamber. The main portion may
have a substantially cylindrical shape with a circular section. It
may have in other embodiments an oval section, or other elongated
shapes. The section of the main portion may be constant, i.e. it
may have the same shape and size along the main portion, or evolve
along the main portion. In other embodiments (not represented), the
main portion of the irradiation chamber may itself be bent, e.g.
being L-shaped or U-shaped, with a rounded elbow between the
branches of said main portion.
The typical volume of an irradiation chamber for small purification
apparatuses is under 200 mL, e.g. around 100 mL. If the irradiation
chamber has an elongated shape, its length may be around 10 cm. If
the internal cross section of the main portion of the irradiation
chamber is constant along its length, the cross section may have a
surface typically comprised 0.5 cm.sup.2 and 4 cm.sup.2. If the
cross section is circular (the main part is a revolution cylinder)
its diameter may be comprised for example between 1 cm and 2
cm.
It must be appreciated that these values are only typical orders of
magnitude which do not limit the scope of the invention.
In any embodiment of the invention, the connecting portion may be
shaped so that they do not comprise any curved surface having a
radius of curvature under 0.5 cm. In an embodiment of the invention
where the main portion of the irradiation chamber is a cylinder of
revolution, the connecting portion may typically be shaped so that
they do not comprise any curved surface having a radius of
curvature under the radius of the cylinder forming the main
portion.
The absence of angles or corners in the irradiation chamber makes
possible to avoid the stagnation of water in said chamber. The
water flows through the chamber and the streamlines follow the
rounded shape of the chamber. This rounded shape makes possible to
prevent an excessive development of bacteria, the formation of a
biofilm, and inorganic deposit in the irradiation chamber.
As used in this specification, the words "comprises", "comprising",
and similar words, are not to be interpreted in an exclusive or
exhaustive sense. In other words, they are intended to mean
"including, but not limited to".
Any reference to prior art documents in this specification is not
to be considered an admission that such prior art is widely known
or forms part of the common general knowledge in the field.
Although the invention has been described by way of example, it
should be appreciated that variations and modifications may be made
without departing from the scope of the invention as defined in the
claims. Furthermore, where known equivalents exist to specific
features, such equivalents are incorporated as if specifically
referred in this specification.
* * * * *